Multilayer films having gas and odor barrier properties are well known and widely used in food and medical packaging applications. Generally, it is desirable for such films to have good impact resistance, flexibility, barrier properties, and desirable optical properties.
Where the films are to be used in medical applications, such as ostomy applications, they must also possess a unique combination of odor and moisture barrier properties as well as low noise, softness, heat or radio-frequency sealability, skin compatibility, and comfort. Such films have been provided in the past through the use of multi-ply film laminates where at least one of the plies is oxygen and moisture vapor impermeable.
In addition to barrier properties, it is often desirable that polymeric films for use in ostomy applications to not emit noise during use, such as when the film is crumpled or bent, so that the presence of the ostomy pouch is concealed from others. In particular, it has been found that the use of ostomy pouches makes the patient feel uneasy about such containers emitting, especially as the patient moves around, noise of a low but still audible intensity level. Most polymeric films, especially multilayer polymer films comprised of individual polymeric film layers having different rigidities (i.e., modulus), emit noise when crumpled. Such noise may alert others to the presence of the ostomy pouch, which can result in embarrassment to the wearer.
Typically, films currently in use for ostomy applications utilize polyvinylidene chloride (PVDC) or copolymers of vinylidene chloride with a comonomer such as methylacrylate or vinylchloride as the gas barrier layer of a multilayer film. These films usually provide good resistance to odor transmission and are also relatively quiet; however, they are also believed to be hazardous to the environment when disposed of by incineration, a common practice in numerous countries.
Unfortunately, previous efforts to provide films formed of chlorine-free barrier resins have tended to be stiffer and noisier than films utilizing conventional PVDC-based resins and do not match the quality of conventional chlorinated films for use in ostomy appliances. Chlorine-free barrier films aimed at providing a suitably soft multilayer film such that the crumpling or bending of the film during use does not emit noise have resulted, undesirably, in the reduction of gas barrier properties.
Accordingly, there still remains a need for polymeric films, particularly being free from chlorine, having both gas and odor barrier properties while also having a softness level such that the amount of noise emitted during use is mitigated.